"Went to Fleet Farm today to do some shopping. Paid for all my items and went to leave, was told I couldn't use the wheelchair to go to the car.

"Returned all my items and had to walk out on my hands and knees. Just trying to make people aware of how Fleet Farm treats handicapped customers," Zahn wrote.

His post has been viewed 11m times and racked up more than 118,000 shares.

Zahn told KIMT that he usually takes his manual wheelchair with him unless he knows a store – like Mills Fleet Farm – has an electric one. On the day of the incident, he said he was dropped off in front of the store and an employee met him with a cart.

The CEO of Mills Fleet Farm, a retail chain of 35 stores in Minnesota, Iowa, Wisconsin, and North Dakota, shared a statement on the company's Facebook page apologising for the incident.

Wayne Sales posted: "We are aware of an unfortunate incident at our Mason City, Iowa, Mills Fleet Farm store where a Mills team member wouldn't allow a disabled person to use an electric cart in our parking lot.

"While use of carts in the parking lot with the uneven terrain can pose a hazard, we feel that in this instance our team member made the wrong decision. We apologize to the customer and to everyone who may be affected."